The US attack on the uranium enrichment facility in Isfahan has delayed Iran‘s nuclear program by years, CIA Director John Ratcliffe told members of Congress last week, according to information provided by a US official to The Associated Press.

The official, who spoke on condition of anonymity, said Ratcliffe said the facility was one of a kind in Iran.

Still, he added that the intelligence community estimates that the vast majority of Iran’s enriched uranium stockpile is buried beneath the ruins at Isfahan and Fordow, two of the three major nuclear facilities attacked by the United States.

The official added that even if the uranium remains intact, the loss of the metal conversion facility has deprived Tehran of the ability to build a bomb for years to come.